Lubricants



Patented Oct. 15, 1946 LUBRICANTS Rush F. McCleary,Beacon, N. Y., assignor to The Texas Company, New York, N. Y., a corporation of Delaware NoDrziwinQg. Application April 12, 1944,

, .Serial No. 530,731

4 Claims. (Cl. 25246.3)

This invention relates to'the use of sulfurized derivatives of compositions derivedfrom cashew nut shell oil in hydrocarbon oils, particularly petroleum oils, to improve the properties of the lubricants compounded therewith.

The present application is a division of pending application S. N. 437,412, filed April 2, 1942.

The naturally-occurring cashew nut shell oil is described in Matiello, J. J Protective & Decorative Coatings, Chap. 2, (1941) as containing approximately 90% anacardic acid '(CzzHszOs) and cardol (032115204) when extracted from the shells by means of solvents. This composition is very unstable and is subject to polymerization, condensation and decomposition on heating.

The usual commercial methods of extracting the oil from the cashew nut shells are incidental to the extraction of the kernel. The cellular structure of the shell is destroyed by a thermal treatment such as a charring or carbonizing process which expels the oil and facilitates removal of the kernel. The extracted shell oil is collected as a dark, thick, viscous liquid whose chemical composition varies in accordance with the degree of heat used in the extraction process.

These thermally extracted oils are described as consisting primarily of anacardic acid, cardanol. CH320) and cardol with cardanol'predominating. The particular proportions ofthese components vary in accordance with the amount of heat used in the xtraction process as, for example, when extracting at low temperatures. of approximately 400 F.,,the extracted oil contains approximately 70% cardanol, whereas extracting at roasting temperatures yields anoil containing approximately 40-60% cardanol.

It has been discovered that the addition of a small quantity of an oil-soluble or oil-miscible sulfurized derivative of cardanol to a refined hydrocarbon oil provides a lubricant or a compounding lubricant which possesses enhanced anti-oxidant or anti-corrosive properties.

The refined hydrocarbon oils which may be improved by the compositions of the present invention include the petroleum lubricating oils used as motor, Diesel, turbine and aviation oil and such hydrocarbon oils as are used in industrial lubricants, greases, textile oils, etc.

Distillation of the commercial cashew nut shell oil carried out either at greatly reduced pressure or steam distillation at atmospheric or reduced pressure yields a distillate consisting almost entirely of cardanol. Cardanol distills over as a light colored liquid at approximately 225 C. and

10 mm. mercury. This compound is described as,

a phenol derivative possessing an unsaturated alkyl radical in the meta position. This compound is very unstable and upon heating forms condensation and polymerization products, together with co-polymers. In addition to the cardanol, the distillate obtained contains a lower boiling fraction possessing a nicotine-like odor which rapidly darkens when exposed to the atmosphere. This fraction which amounts to about 5% of the original oil contains approximately 0.64% nitrogen. If desired, this lower boiling fraction may be separated by fractional distillation.

Another method of obtaining cardanol is the destructive distillation of the solvent extracted cashew nut shell oil. The yields obtained will vary according to the degree of decomposition ,of the solvent extracted oil. The following physical constants were obtained on a sample of a distillate obtained by distilling the commercially available thermal extracted cashew nut shell oil at 10 mm. Hg.

Bromine No 135 Hydroxyl No 183 Neutralization No 6 Refractive index N 1.4973

The term cardanolf as used throughout the specification and. claims, unless otherwise stated, is meant to include not only the specific compound which has a constant boiling point at approximately 225" C. and 10 mm. Hg but also the distillation products obtained by the distillation ofthe thermal extracted cashew nut shell oil at reduced pressures or by steam distillation at atmospheric or reduced pressure and the distillate obtained by the destructive distillation of the solvent extracted cashew nut shell oil together with such fractions obtained from cashew nut shell oil which contain a major portion of cardanol.

These oil-soluble or oil-miscible sulfurized derivatives of the present invention may be incorporated in a hydrocarbon oil in amounts varying between 0.01 to 5% by weight of the finished lubricant. The particular proportions used depend upon the type of lubricant to be improved, the service for which the lubricant is intended and the degree of improvement desired in the hydrocarbon oil. It is to be noted that in many instances, especially in the compounding of lubrieating oils, the additives of the present invention will be used in combination with a detergent additive in the finished lubricant and, therefore, the amounts used will depend upon the type of detergent additive together with its compatibility. The preferred range of proportions in a mineral lubricating oil when used in a few of the more common services is as follows:

Per cent by weight of finished lubricant Diesel lubricating oil 0.5 -2.5 Motor lubricating oil 0.5 -3.0 Heavy duty lubricating oil 0.5 -3.0 Turbine lubricating oil 0.01-0.10 Airplane lubricating oil 0.5 -2.0

In preparing the oil-soluble sulfurized derivatives care must be taken to avoid the polymerization reactions which normally attend the addition of sulfur to cardanol, In th usual reaction of sulfur with cardanol, polymerization products are obtained which range from semi solid to solid rubbery materials which are oilinsoluble. It has been found preferable to avoid these reactions by stabilizing the cardanol prior to the sulfurization reactions by means of a hydrogenation reaction which reduces the degree of unsaturation. In this manner the cardanol is rendered sufficiently stable to enable a majority of the usual sulfurization reactions to be employed in preparing the oil-soluble derivative.

Although it is preferred to use a stabilizing reaction such as partial hydrogenation prior to sulfurization, other methods may be employed.

One of these methods which avoids the hydroge- EXAMPLE An ethyl alcohol solution of 514 grams of the distillate obtained from the distillation of commercially available cashew nut shell oil was charged in a hydrogenation bomb with 10-15 grams of Raney nickel catalyst and treated with hydrogen under pressure. The temperature was controlled by external heat and varied between 50 F. at the start to 200 F. near the end. The product, after being freed of catalyst and solvent, weighed 495 grams and had a bromine number of 80. 1000 grams of the partially hydrogenated cardano1.and 115 grams of sulfur were heated together at 150-155 C. for 3 hours. The .sulfurized product was dissolved in an equal weight of lubricating oil to form a 50% concentrate.

The effectiveness of the composition of the present invention as an improving agent for lubricants was demonstrated by an empirical test designed to demonstrate the anti-oxidant or anti-corrosive properties of the additive ingredient of a lubricating oil. This test consists of a copper-lead bearing specimen encased in a special non-wearing bushing, rotatively mounted on a stainless steel shaft and immersed in a glass pot of the oil to be tested. The oil was heated to a controlled temperature of either 250 F. or 350 F. and continuously circulated between the bearing specimen and the shaft for 10 hours. Throughout the test the oil was continuously agitated by means of copper bafiles which acted as oxidation accelerators. The bearing specimen was weighed before the test and after the 10- hour period and the loss of weight recorded in milligrams. The reference oil of this test was a solvent-refined, dewaxed, Mid-Continent lubrieating oil of an SAE 30 grade. The following results were obtained 0n the uninhibited reference oil and the reference oil compounded with an additive of the present invention:

BEARING CORROSIONCOPPER-LEAD (10 HOURS) Loss of weight, mgs.

; Reference oil 13 Reference oil+1.0% of sulfurized partially hydrogenated cardanol (Example) 0 The hydrocarbon oils to which the oil-soluble sulfurized derivatives of the present invention are added may be either in the crude form or partially or highly refined and may contain'other additive ingredients such as dyes, metal soaps, pour depressants, thickeners, V. I. improvers, oilineSs agents, extreme pressure agents, sludge dispersers, oxidation inhibitors, and corrosion in-- hibitors such as sulfurized hydrocarbons, etc.

Obviously many modifications and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and scope thereof and, therefore, only such limitations should be imposed as are indicated in the appended claims.

I claim:

1. A lubricant comprising a hydrocarbon oil and a small quantity, less than 5% by weight, of an oil-soluble sulfurized derivative of partially hydrogenated cardanol.

2. A lubricant comprising a mineral lubricating oil and 0.015.0% by weight of an oil-soluble sulfurized'derivative of partially hydrogenated cardanol.

3. .A lubricant comprising a hydrocarbon oil having incorporated therein 0.01-5.0% by weight 1 of an oil-soluble sulfurized derivative of partially hydrogenated cardanol. I

4. A lubricant comprising a hydrocarbon oil having incorporated therein 0.01-5.0% by weight of an oil-soluble sulfurized derivative of a partially hydrogenated phenolic distillate obtained from the distillation of cashew nut shell oil.

RUSH F. MCCLEARY. 

